Field of the Invention
The invention relates to a circuit for recovering a digital signal from an input signal received by way of galvanic separation, comprising two input terminals for the input signal and one output terminal for the recovered digital signal.
In the transmission of electrical signals between two systems A and B, it is frequently required that systems A and B must not be galvanically (metallically) connected to one another, that is to say there must not be a direct metallic connection between systems A and B. To galvanically isolate systems A and B, which are intended to exchange signals with one another, the insertion of a capacitor in each of the signal transmission lines or the use of a transformer for a pair of signal lines is possible in line-connected signal transmission. Accordingly, the coupling elements of capacitor or transformer, respectively, allow the transmission of signals between systems A and B without connecting these to one another galvanically.
However, the use of the coupling elements causes a change in the signal variation so that in the transmission of a signal from system A to system B, a device must be provided in system B by means of which the signal variation originally output by system A can be recovered. This is required especially in the case of digital signals because the digital signal processing devices in the receiving system B only operate reliably with defined signal structures.